CZ289350B6 - Glass composition, intended particularly for use in dental technology, glass pins and biologically compatible dental supporting pins produced therefrom as well as process for producing such glass pins - Google Patents

Abstract

The present invention relates to a glass composition, intended particularly for use in dental technology, especially for preparing dental glass pins and biologically compatible dental supporting pins as well as process for producing such glass pins. Glass material contains a high percentage of boron oxide, which makes it possible to reduce content of alkali oxides. So obtained dental glass pins are biologically compatible and they can be used when preparing tooth bridges particularly when posterior teeth serving as support of said bridge are missing.

Description

Technical field

The present invention relates to a novel glass composition for use in dental technology, in particular for the preparation of glass pins and biocompatible dental support pins, glass pins and biocompatible dental support pins made therefrom, and a method for producing such glass pins.

BACKGROUND OF THE INVENTION

The lack of teeth interferes with the perfect closure of the dentition and the harmony of chewing. Neglecting it greatly affects somatic and mental harmony. Loss of molar teeth is the most common case that can be replaced initially by inserting a bridge. However, the formation of a permanent bridge may be prevented by the loss of the posterior tooth that supports the end of the row. Only a removable prosthesis can solve this problem. Insufficient chewing due to lack of substitute teeth may negatively affect stomach and intestinal functions. It also changes the aesthetic appearance, which can lead to mental disorders.

Several methods of tooth replacement are known, including, but not limited to, methods of providing special dental bridges with fixed or non-fixed ends, the use of which may lead to known problems.

Hungarian Patent 210,237, issued November 1, 1994, relates to the replacement of missing posterior teeth with a metal bridge provided with a glass pin and to a method for producing said metal bridge. The dental bridge of the above patent comprises a conventional metal bridge body and one or more glass pins attached to the metal bridge body by its tapered ends. The principle of the patent is that the glass bolt supporting the metal bridge is made of fused glass and corresponds to the shape of the tooth seat and the glass bolt or, in the case of several glass bolts, at least one of them is fixed to the end rear member of the metal bridge. In the manufacture of the metal bridge, the molten glass rod is pushed into a suitable location of the model produced by the conventional method, followed by slow cooling of the glass mold corresponding to the shape of the saddle and after cooling the sides opposite the gums are grinded and trimmed. model and fastened to a pre-prepared metal bridge. The glass pin, which was made by a German dentist from a cullet already in 1936, was similar to that described, but the melting point was formed only by grinding.

According to the aforementioned Hungarian patent, the glass rod was melted at a temperature of 524 ° C to 526 ° C. A suitable glass composition disclosed is: 73.0% SiO ₂ ; 7.0% B ₂ O ₃ / As ₂ O ₃ / Al ₂ O ₃ ; 2.5-5% MgO and the remainder was a mixture of ZnO / BaO / PbO / Fe ₂ O ₃ / Na ₂ O / K ₂ O.

The durability of special dental bridges with a non-fixed end can be substantially increased by using a support pin (or multiple support pins) adapted to the corresponding gum shape. A number of requirements can be determined with respect to the properties of the fastener of circular or elliptical cross-sectional shape. The most important requirements are:

(a) appropriate strength to withstand the chewing stress, long-term resistance to chemical reactions occurring in the mouth;

(b) long-term tissue tolerability and inactivity when used in the human body;

- 1 GB 289350 B6

(c) the relevant softening characteristics of the dental laboratory and subsequent plasticity, so that its structure remains inactive and its strength is maintained even when chewed.

Experience has shown that inorganic glasses meet these requirements in particular. However, due to their composition, most glasses are not suitable for dental purposes. Some other glasses can be used as a compromise solution. Therefore, it is necessary to obtain glass of a special composition meeting the best described conditions of use. It was an object of the present invention to provide such a glass of special composition.

The so-called support pin formed as a support for the free end of the dental bridge must have considerable mechanical resistance to withstand the generally known high pressure and shear forces that occur during chewing, even considering the altered tension distribution compared to conventionally fixed bridges. Stress-free silicate glass seems to be suitable for this purpose, whose modulus of elasticity is usually in the range 500 to 800 mPa and its compressive strength is high compared to conventional plastics materials.

The degree of Mohs hardness of 5-7 of this glass is high enough to provide a support pin that would not be scratched by food. Specifically, surface micro-cracks play an important role in fractures. Such micro-cracks could impair the mechanical properties of the pin. This glass exhibits high abrasion resistance, although in the application according to the invention it is clear that it will not be subjected to as intense erosion as the teeth.

The thermal and electrical conductivity of the glass is low. There is no risk of glass forming a galvanic cell in the mouth and accelerating the corrosion of parts made of other metals and built in the mouth.

In particular, the structural material to be inserted should have chemical resistance. Silicate glasses usually meet this requirement. However, the interaction between glass and solutions with which the glass is in contact, such as saliva, should be considered. These reactions can in principle be divided into two processes which interact with each other. As a result of the first process, hydrogen ions come to the surface of the glass from the solution, slowly penetrating into the interior of the glass. At the same time, the alkali ions, especially sodium ions, pass into solution in an amount equivalent to hydrogen ions. This partial process creates an alkaline solution. The second process results in a slow degradation of the polymeric structure of the glass, during which all the glass-forming elements pass into solution. Both processes usually proceed slowly at normal body temperatures, but the rate may vary depending on the composition of the glass. In a disadvantageous case, a substantial local increase in pH and / or dissolution of toxic materials harmful to the organism should be considered.

The choice of material structure and the simplicity of the technology to be used are also important factors. This means that the support pin could be formed and fastened in the bridge in conventional dental mechanical laboratories relatively easily and in a short time. A dental glass pin is particularly preferred in this respect. The glass pin according to the invention can be simply heated up to the appropriate temperature, then pressed into the appropriate location of the gypsum model, in particular using a tool designed for this purpose, and then cooled properly to avoid adverse stresses in the mass. The aforementioned Hungarian patent does not meet all of these requirements.

It is an object of the present invention to provide a fully biocompatible material which can also be prepared commercially such that the physical and chemical characteristics of all parts of the product consistently meet the above-mentioned essential requirements.

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SUMMARY OF THE INVENTION

An object of the present invention is a glass composition for dental technology consisting of up to 75 wt. silicon dioxide Si0 ₂ to 18 wt%. % boron oxide B ₂ 0 ₃ , up to 8 wt. sodium oxide Na ₂ O,

0.5 to 2.0 wt. potassium oxide K ₂ O,

0.8 to 2 wt. of aluminum oxide Al ₂ 0 ₃ .

Another aspect of the present invention is a glass pin suitable for preparing a biocompatible dental support pin made of the glass composition of the present invention, one end of which is molded into a shape suitable for post-treatment and placement in the dental bridge and the other end is a convex surface.

A further feature of the invention is a process for producing a glass pin according to the invention which comprises heating the glass composition of the invention to a temperature of 900 ° C to 1200 ° C, molding it into a mold in a mold and then continuously cooling it to room temperature in one step. .

The invention further encompasses the use of the present glass composition in the preparation of a biocompatible dental support post for a concealed or uncovered dental bridge made of metal or other material.

Further, the invention includes the use of the glass pin of the present invention in the preparation of a biocompatible dental support pin for a concealed or uncovered dental bridge made of metal or other material.

In testing the composition, it has been reported that it may contain insignificant amounts of zinc and magnesium as accompanying impurities (Zn 0.01 wt% and MgO 0.006 wt%) in addition to the main ingredients, but remain inactive and unable to affect irritation and cause health damage. The composition does not contain lead or barium, which are harmful to health.

The physical characteristics of the material are:

The glass material is melted in an oven at a temperature of 1560 ° C - 1600 ° C.

Working temperature: 1400 ° C.

Coefficient of linear expansion: 4 - 4.2.10 ^-6 K ^-1 .

Compressive strength: 120-150 mPa.

Acid resistance: hydrolytic class I.

Alkaline resistance: hydrolytic class II.

The softening temperature is low enough to allow the material to be formed by the heat sources available in the dental laboratory. This advantageous property is due to the high borate content, which makes it possible to reduce the otherwise indispensable high alkali metal content.

-3GB 289350 B6

Reducing the sodium oxide concentration very advantageously affects chemical resistance. On the one hand, a low alkali metal content is advantageous because the amount of materials passing from glass due to corrosion into the body is small and also that the negligible amount of dissolved components is non-toxic. On the other hand, it is an advantage that due to the low concentration of sodium 5, corrosion does not cause a substantial increase in pH values near the gums.

An advantage of the present invention is that the glass pin is made of the above glass composition, which is preferably available in a form suitable for use in a dental laboratory.

According to the process described in the aforementioned Hungarian patent, a glass pin is formed by pressing a glass rod into the model. The glass rod has to melt over a relatively large length and, while being pressed into the model, the glass rod tends to deform along the longitudinal axis of the glass rod. Accordingly, the method is complicated and without the appropriate skill there is a risk of high waste.

The composition of the material and hence the physical and chemical characteristics of the glass according to the present invention are constant, which ensures easy handling.

The invention is further elucidated by the accompanying drawings, wherein Fig. 1 shows a manufacturing process of a preformed glass pin used for the manufacture of a biocompatible dental support pin. Giant. 2 is a cross-sectional view of a preformed glass pin and a special tool (fastening tool) used to apply the glass pin. Giant. 3 shows a cross-section of a biocompatible dental support post positioned on the gum, the shape of which is shaped thereto.

The preferred method of manufacturing and using the glass of the present invention is explained in detail below by way of example.

Exemplary embodiment

Example

The glass melts from a base material whose composition corresponds to the above description at 1580 ° C 35 to 1600 ° C, preferably in an oven designed and maintained for this purpose (in the case of an oven used for other purposes, particles remaining on the crucible walls may lead to unwanted contamination, so it is advisable to remove them), then 4 mm thick glass rods are pulled out. The glass rods are cooled by controlled cooling to avoid undue internal stresses, because the heated glasses, depending on the material composition, react in different ways to the outside temperature. Adverse stresses may occur in the glass of the present invention during rapid cooling, therefore cooling of the base material until cooling below 450 ° C has to be used.

The bars thus produced form the base material (blank) for the production of the glass pin. The tools used to manufacture the glass bolts are: an oxygen-propane burner, a pressure press comprising the glass bolt shape of Figure 1, a pliers and a heat chamber or thermal insulating pad to cool the final product according to this technology.

The most advantageous process for producing a glass pin according to the invention is that the preformed glass rods are heated by means of a burner to 900 ° C to 1200 ° C and pressed into a mold preheated to 600 ° C to 700 ° C and kept at a temperature of 600 ° C. up to 700 ° C with a special burner. The mold should be kept at this temperature because at higher temperatures the material could stick to the tool and at lower temperatures the product could cool too quickly and this would create harmful stress. After the glass has taken the shape of a mold (about 1 second)

Separate the rod from the bar by flame, remove the pin from the die by extrusion darkness and place in a heat chamber where it is gradually cooled to room temperature.

Subsequently, the convex surface formed at the point of separation is polished perpendicular to the longitudinal axis by diamond discs, thereby facilitating further dentist work.

The glass pin thus obtained is ready for commercial sale or direct use.

Dentist's work on forming a biocompatible dental support post is done as follows:

The glass pin is placed in the clamps of FIG. 2 and heated with an oxygen / propane burner to a white heat at a temperature of about 900 ° C to 1200 ° C until the material softens and becomes deformable.

The softened material is pushed perpendicularly to the wall to the location indicated on the prepared gypsum model, then the surface is reheated repeatedly for a short time by holding it above the flame, then inserted and covered with ceramic materials. the whole mass at least below 450 ° C, thus avoiding harmful stresses on the pressed surface.

The end of the biocompatible dental support pin opposite to the pressed surface is formed as required for insertion into the bridge, using a diamond cutter and diamond grinder commonly used in the glass industry. The biocompatible dental support pin prepared in this way is adjusted to match the tooth pin on the model and fixed to the finished bridge with cement.

The biocompatible dental support pins made of glass according to the invention and / or the biocompatible dental support pins according to the invention were used in about 150 patients who were subjected to periodic macro-examinations, X-ray examinations and, if possible, tests of fixed and later removed dental bridge. No pathological changes were detected, either in the environment under the biocompatible dental support pin or in the surrounding area. Comparison of the panoramic X-ray images before and after work revealed that the outlines of the bone under the biocompatible dental support pin and the last pin tooth were the same.

PATENT CLAIMS

Claims (5)

What is claimed is: 1. A glass composition, in particular for use in the dental technique, comprising: 70 to 75 wt. SiO ₂ , 12 to 18 wt. boron oxide B2O3 4 to 8 wt. sodium oxide Na ₂ 0, 0.5 to 2.0 wt. potassium oxide K ₂ O, 0.8 to 2 wt. of aluminum oxide Al ₂ 0 ₃ . A glass pin suitable for the preparation of a biocompatible dental support pin, characterized in that it is made of a glass composition according to claim 1, one end of which is molded into a shape suitable for post-treatment and placement in the dental bridge and the other end is a convex surface. -5I A method for producing a glass pin according to claim 2, characterized in that the glass composition according to claim 1 is heated to a temperature of 900 ° C to 1200 ° C, pressed into a mold in a mold and then continuously cooled in one step to room temperature. Use of a glass composition according to claim 1 in the preparation of a biocompatible dental support post for a concealed or uncovered dental bridge made of metal or other material. Use of a glass pin according to claim 2 in the preparation of a biocompatible dental 10 shows a support pin for a concealed or uncovered dental bridge made of metal or other material.